138026639 has 4 divisors (see below), whose sum is σ = 140963424. Its totient is φ = 135089856.

The previous prime is 138026617. The next prime is 138026653. The reversal of 138026639 is 936620831.

138026639 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 936620831 = 17 ⋅55095343.

It is a cyclic number.

It is not a de Polignac number, because 138026639 - 2²⁰ = 136978063 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138026699) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1468322 + ... + 1468415.

It is an arithmetic number, because the mean of its divisors is an integer number (35240856).

Almost surely, 2^138026639 is an apocalyptic number.

138026639 is a deficient number, since it is larger than the sum of its proper divisors (2936785).

138026639 is an equidigital number, since it uses as much as digits as its factorization.

138026639 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2936784.

The product of its (nonzero) digits is 46656, while the sum is 38.

The square root of 138026639 is about 11748.4739008945. The cubic root of 138026639 is about 516.7981745483.

The spelling of 138026639 in words is "one hundred thirty-eight million, twenty-six thousand, six hundred thirty-nine".